It's no doubt a rare thing for America to become less litigious on any given issue. But the growth in lawsuits under one law in particular — the Fair Labor Standards Act, which sets the nation's minimum-wage and overtime levels — has been particularly dramatic.

The employer-side law firm Seyfarth Shaw observed this in a blog post a few days ago. The number of wage and hour cases filed in federal court rose to 8,871 for the year ending Sept. 30, up from 1,935 in 2000. That's an increase of 358 percent, compared to the the federal judiciary's overall intake volume, which rose only a total of about 7 percent over the same period. (In absolute numbers, the category is still smaller than many, such as insurance and habeas corpus claims.)

So why the huge increase? Seyfarth Shaw's attorneys think is has to do with increased attention being drawn to wage and hour issues by a Labor Department that's been cracking down on misclassification of independent contractors, moving to change overtime rules, and promoting minimum-wage hikes on the local level. The lawyers also argue that the Fair Labor Standards Act, originally enacted in 1938, has failed to adapt from an industrial to a service-based economy, creating ambiguities that often have to be litigated to resolve (witness the lawsuits over the employment status of Uber drivers and other "gig workers").

But there's another reason, says Samuel Estreicher, director of the Center for Labor and Employment Law at New York University Law School. As unions have declined, lawyers are suing less under the laws that govern labor-management relations and more over wages and hours, gaining familiarity with the statute as they go.

"When I started out in practice, nobody really heard of the Fair Labor Standards Act," Estreicher says. "Then in the 80s, and during the Clinton years, some lawsuits were brought with respect to some fairly high-earning employees. So I think this is the growth area for plaintiffs-side attorneys." In addition, he says, employers just keep trying to treat their workers like independent contractors when they're really not, fueling the rise in misclassification lawsuits in industries such as construction and warehousing.

It's unclear how much of the decline in union-related litigation has to do with the rise in wage and hour litigation, but it is possible that issues that before might have been sorted out through contract enforcement are now more often resolved in the courts. Here's a chart of the growth in FLSA suits and the decline in cases brought under the National Labor Relations Act (using data for the years ending in March, the latest available from USCourts.gov):

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And just for the sake of comparison, here's a chart of the overall civil caseload for different categories, including all labor laws together:

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